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[PMID]: 28418580 [Au] Autor: Fukai N; Kitagawa S; Ohtani H [Ad] Endereço: Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan. [Ti] Título: Effect of surfactant species and electrophoretic medium composition on the electrophoretic behavior of neutral and water-insoluble linear synthetic polymers in nonaqueous capillary zone electrophoresis. [So] Source: Electrophoresis;38(13-14):1724-1729, 2017 07. [Is] ISSN: 1522-2683 [Cp] País de publicação: Germany [La] Idioma: eng [Ab] Resumo: We have recently demonstrated the separation of neutral and water-insoluble linear synthetic polymers in nonaqueous capillary zone electrophoresis (NACZE) using a cationic surfactant of cetyltrimethylammonium chloride (CTAC). In this study, eight ionic surfactants were investigated for the separation of four synthetic polymers (polystyrene, polymethylmethacrylates, polybutadiene, and polycarbonate); only three surfactants (CTAC, dimethyldioctadecylammonium bromide, and sodium dodecylsulfate) caused their separation. The order of the interaction between the polymers and the surfactants depended on both the surfactant species and the composition of the electrophoretic medium. Their investigation revealed that the separation is majorly affected by the hydrophobic interactions between the polymers and the ionic surfactants. In addition, the electrophoretic behavior of polycarbonate suggested that electrostatic interaction also affects the selectivity of the polymers. [Mh] Termos MeSH primário: Eletroforese Capilar/métodos Polímeros/química Polímeros/isolamento & purificação Tensoativos/química [Mh] Termos MeSH secundário: Ânions/química Compostos de Bis-Trimetilamônio/química Interações Hidrofóbicas e Hidrofílicas [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T [Nm] Nome de substância: 0 (Anions); 0 (Bis-Trimethylammonium Compounds); 0 (Polymers); 0 (Surface-Active Agents); 0 (cethyltrimethylammonium chloride) [Em] Mês de entrada: 1709 [Cu] Atualização por classe: 171106 [Lr] Data última revisão: 171106 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170419 [St] Status: MEDLINE [do] DOI: 10.1002/elps.201700013

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[PMID]: 27997185 [Au] Autor: Pernak J; Giszter R; Biedziak A; Niemczak M; Olszewski R; Marcinkowska K; Praczyk T [Ad] Endereço: Department of Chemical Technology, Poznan University of Technology , Poznan 60-965, Poland. [Ti] Título: Alkyl(C , C , C )trimethylammonium-Based Herbicidal Ionic Liquids. [So] Source: J Agric Food Chem;65(2):260-269, 2017 Jan 18. [Is] ISSN: 1520-5118 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: In the framework of this study a synthesis methodology and characterization of long alkyl herbicidal ionic liquids (HILs) based on four commonly used herbicides (2,4-D, MCPA, MCPP, and dicamba) are presented. New HILs were obtained with high efficiency (>95%) using an acid-base reaction between herbicidal acids and hexadecyltrimethylammonium, octadecyltrimethylammonium, and behenyltrimethylammonium hydroxides in alcoholic medium. Among all synthesized salts, only three compounds comprising the MCPP anion were liquids at room temperature. Subsequently, the influence of both the alkyl chain length and the anion structure on their physicochemical properties (thermal decomposition profiles, solubility in 10 representative solvents, surface activity, density, viscosity, and refractive index) was determined. All HILs exhibited high thermal stability as well as surface activity; however, their solubility notably depended on both the length of the carbon chain and the structure of the anion. The herbicidal efficacy of the obtained salts was tested in greenhouse and field experiments. Greenhouse testing performed on common lambsquarters (Chenopodium album L.) and flixweed (Descurainia sophia L.) as test plants indicated that HILs were characterized by similar or higher efficacy compared to commercial herbicides. The results of field trials confirmed the high activity of HILs, particularly those containing phenoxyacids as anions (MCPA, 2,4-D, and MCPP). [Mh] Termos MeSH primário: Herbicidas/química Herbicidas/farmacologia Líquidos Iônicos/química [Mh] Termos MeSH secundário: Ácido 2,4-Diclorofenoxiacético/química Ácido 2-Metil-4-clorofenoxiacético/química Compostos de Bis-Trimetilamônio/química Brassicaceae/efeitos dos fármacos Técnicas de Química Sintética Chenopodium album/efeitos dos fármacos Dicamba/química Herbicidas/síntese química Líquidos Iônicos/síntese química Líquidos Iônicos/farmacologia Plantas Daninhas/efeitos dos fármacos Polônia Solubilidade Relação Estrutura-Atividade Propriedades de Superfície Viscosidade [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Bis-Trimethylammonium Compounds); 0 (Herbicides); 0 (Ionic Liquids); 2577AQ9262 (2,4-Dichlorophenoxyacetic Acid); D888C394VO (2-Methyl-4-chlorophenoxyacetic Acid); SJG3M6RY6H (Dicamba) [Em] Mês de entrada: 1705 [Cu] Atualização por classe: 170502 [Lr] Data última revisão: 170502 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 161221 [St] Status: MEDLINE [do] DOI: 10.1021/acs.jafc.6b04528

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[PMID]: 27456123 [Au] Autor: Carvalho FA; Alves FR; Tabak M [Ad] Endereço: Instituto de Química de São Carlos, Universidade de São Paulo, Brazil; Faculdade de Química, Universidade Federal do Sul e Sudeste do Pará, Brazil. Electronic address: adrianocarbureto@gmail.com. [Ti] Título: Ionic surfactants-Glossoscolex paulistus hemoglobin interactions: Characterization of species in the solution. [So] Source: Int J Biol Macromol;92:670-681, 2016 Nov. [Is] ISSN: 1879-0003 [Cp] País de publicação: Netherlands [La] Idioma: eng [Ab] Resumo: Glossoscolex paulistus hemoglobin (HbGp) is an oligomeric multisubunit protein with molecular mass of 3600kDa. In the current study, the interaction of sodium dodecyl sulfate (SDS) and cetyl trimethylammonium chloride (CTAC) surfactants with the monomer d and the whole oxy-HbGp, at pH 7.0, was investigated. For pure monomer d solution, SDS promotes the dimerization of subunit d, and the monomeric and dimeric forms have sedimentation coefficient values, s , around 2.1-2.4 S and 2.9-3.2 S, respectively. Analytical ultracentrifugation (AUC) and isothermal titration calorimetry (ITC) data suggest that up to 26 DS anions are bound to the monomer. In the presence of CTAC, only the monomeric form is observed in solution for subunit d. For the oxy-HbGp, SDS induces the dissociation into smaller subunits, such as, monomer d, trimer abc, and tetramer abcd, and unfolding without promoting the protein aggregation. On the other hand, lower CTAC concentration promotes protein aggregation, mainly of trimer, while higher concentration induces the unfolding of dissociated species. Our study provides strong evidence that surfactant effects upon the HbGp-subunits are different, and depend on the surfactant: protein concentration ratio and the charges of surfactant headgroups. [Mh] Termos MeSH primário: Hemoglobinas/metabolismo Oligoquetos/metabolismo Tensoativos/metabolismo [Mh] Termos MeSH secundário: Animais Área Sob a Curva Compostos de Bis-Trimetilamônio/metabolismo Calorimetria Difusão Dinâmica da Luz Hidrodinâmica Íons Modelos Moleculares Ligação Proteica Dodecilsulfato de Sódio/metabolismo Soluções Ultracentrifugação [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Bis-Trimethylammonium Compounds); 0 (Hemoglobins); 0 (Ions); 0 (Solutions); 0 (Surface-Active Agents); 0 (cethyltrimethylammonium chloride); 368GB5141J (Sodium Dodecyl Sulfate) [Em] Mês de entrada: 1703 [Cu] Atualização por classe: 170313 [Lr] Data última revisão: 170313 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 160727 [St] Status: MEDLINE

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[PMID]: 27294701 [Au] Autor: Zhang YJ; Yang ZH; Song PP; Xu HY; Xu R; Huang J; Li J; Zhou Y [Ad] Endereço: College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China. [Ti] Título: Application of TiO2-organobentonite modified by cetyltrimethylammonium chloride photocatalyst and polyaluminum chloride coagulant for pretreatment of aging landfill leachate. [So] Source: Environ Sci Pollut Res Int;23(18):18552-63, 2016 Sep. [Is] ISSN: 1614-7499 [Cp] País de publicação: Germany [La] Idioma: eng [Ab] Resumo: This study investigated the treatment performance for aging leachate containing refractory organic pollutants by TiO2-organobentonite photocatalyst combined with polyaluminum chloride (PAC) coagulant. TiO2 was immobilized on organobentonite granules as a supporter modified by cetyltrimethylammonium chloride (CTAC). The prepared catalysts were characterized by ESEM, FTIR, and XRD analysis, which showed that TiO2-organobentonite catalyst had uniform coating of TiO2 on support. Chemical oxygen demand (COD) and NH3-N removal rates by combination of TiO2-CTAC2.0 photocatalysis and PAC coagulation were evaluated, optimized, and compared to that by either treatment alone, with respect to TiO2-CTAC2.0 dose, photocatalytic contact time, pH, and PAC dose. Furthermore, higher removal rates (COD 80 %; NH3-N 46 %) were achieved by response surface methodology (RSM) when TiO2-CTAC2.0 photocatalysis was followed by PAC coagulation at optimized conditions. The optimized experimental conditions were TiO2-CTAC2.0 dosage of 5.09 g/L, at pH 5.53, photocatalytic contact time for 180 min, and PAC dosage of 1062 mg/L. [Mh] Termos MeSH primário: Compostos de Bis-Trimetilamônio/química Eliminação de Resíduos/métodos Titânio/química Poluentes Químicos da Água/química [Mh] Termos MeSH secundário: Hidróxido de Alumínio/análise Bentonita/química Análise da Demanda Biológica de Oxigênio Compostos de Bis-Trimetilamônio/análise Catálise Compostos de Cetrimônio Coagulantes Poluentes Químicos da Água/análise [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Bis-Trimethylammonium Compounds); 0 (Cetrimonium Compounds); 0 (Coagulants); 0 (Water Pollutants, Chemical); 0 (cethyltrimethylammonium chloride); 1302-78-9 (Bentonite); 1327-41-9 (aluminum oxychloride); 15FIX9V2JP (titanium dioxide); 5QB0T2IUN0 (Aluminum Hydroxide); D1JT611TNE (Titanium); Z7FF1XKL7A (cetrimonium) [Em] Mês de entrada: 1704 [Cu] Atualização por classe: 171103 [Lr] Data última revisão: 171103 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 160614 [St] Status: MEDLINE [do] DOI: 10.1007/s11356-016-7031-4

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[PMID]: 26730682 [Au] Autor: Sokolov I; Zorn G; Nichols JM [Ad] Endereço: Departments of ME, BME, Physics, Tufts University, Medford, MA 02155, USA. igor.sokolov@tufts.edu. [Ti] Título: A study of molecular adsorption of a cationic surfactant on complex surfaces with atomic force microscopy. [So] Source: Analyst;141(3):1017-26, 2016 Feb 07. [Is] ISSN: 1364-5528 [Cp] País de publicação: England [La] Idioma: eng [Ab] Resumo: The study of molecular adsorption on solid surfaces is of broad interest. However, so far the study has been restricted to idealized flat smooth rigid surfaces which are rarely the case in real world applications. Here we describe a study of molecular adsorption on a complex surface of the submicron fibers of a fibrous membrane of regenerated cellulose in aqueous media. We use a cationic surfactant, cetyltrimethylammonium chloride (CTAC), as the adsorbing molecule. We study the equilibrium adsorption of CTAC molecules on the same area of the fibers by sequentially immersing the membrane in pure water, 1 mM and then a 20 mM solution of CTAC. Atomic force microscopy (AFM) is applied to study the adsorption. The force-volume mode is used to record the force-deformation curves of the adsorbed molecules on the fiber surface. We suggest a model to separate the forces due to the adsorbed molecules from the elastic deformation of the fiber. Interestingly, knowledge of the surface geometry is not required in this model provided the surface is made of elastically homogeneous material. Different models are investigated to estimate the amount of the adsorbed molecules based on the obtained force curves. The exponential steric repulsion model fits the force data the best. The amount of the adsorbed surfactant molecules and its dependence on the concentration are found to be reasonable compared to the data previously measured by means of Raman scattering done on a flat surface of silica. [Mh] Termos MeSH primário: Compostos de Bis-Trimetilamônio/química Microscopia de Força Atômica Tensoativos/química [Mh] Termos MeSH secundário: Adsorção Membranas Artificiais Dióxido de Silício/química Propriedades de Superfície Água/química [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T [Nm] Nome de substância: 0 (Bis-Trimethylammonium Compounds); 0 (Membranes, Artificial); 0 (Surface-Active Agents); 0 (cethyltrimethylammonium chloride); 059QF0KO0R (Water); 7631-86-9 (Silicon Dioxide) [Em] Mês de entrada: 1701 [Cu] Atualização por classe: 170110 [Lr] Data última revisão: 170110 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 160106 [St] Status: MEDLINE [do] DOI: 10.1039/c5an01941a

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[PMID]: 25641038 [Au] Autor: Modir-Rousta A; Bottaro CS [Ad] Endereço: Department of Chemistry, Memorial University of Newfoundland, St. John's, NL, Canada. [Ti] Título: New pressure-assisted sweeping on-line preconcentration for highly polar environmentally relevant nitrosamines: Part 2. Cationic and anionic surfactants with zero-flow capillaries. [So] Source: Electrophoresis;36(7-8):1016-23, 2015 Apr. [Is] ISSN: 1522-2683 [Cp] País de publicação: Germany [La] Idioma: eng [Ab] Resumo: We recently introduced a pressure-assisted sweeping-reversed migration-EKC (RM-EKC) method for preconcentration of neutral polar N-nitrosamines with low affinity for the micellar phase. The type of surfactant and phase ratio are dominant factors in dictating the magnitude of interactions between analyte and micellar phase, thus four surfactants (anionic and cationic) with a range of functionalities (SDS, ammonium perfluorooctanoate (APFO), bile salts, and cetyltrimethylammonium chloride (CTAC)) were evaluated for sweeping-RM-EKC of highly polar N-nitrosamines. All gave acceptable results for sweeping-RM-EKC when used in high concentrations (≥200 mM) with low EOF. While no single surfactant was superior by all measures, all but the bile salts had useful performance characteristics. APFO showed the narrowest peak widths and highest number of theoretical plates, though two species co-migrated at all concentrations (25-300 mM); SDS and the cationic surfactant CTAC also showed good separation characteristics and could resolve all peaks, but CTAC had wider separation window. Various types of capillaries coated for EOF control were compared for use with anionic and cationic surfactants. A commercial zero-EOF capillary coated with a polymer bearing sulfonic acid functional groups showed superior EOF suppression and reproducibility of migration time with all surfactants. [Mh] Termos MeSH primário: Cromatografia Capilar Eletrocinética Micelar/métodos Eletroforese Capilar/métodos Nitrosaminas/análise Tensoativos/química [Mh] Termos MeSH secundário: Compostos de Bis-Trimetilamônio/química Nitrosaminas/química Pressão Reprodutibilidade dos Testes [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T [Nm] Nome de substância: 0 (Bis-Trimethylammonium Compounds); 0 (Nitrosamines); 0 (Surface-Active Agents); 0 (cethyltrimethylammonium chloride) [Em] Mês de entrada: 1605 [Cu] Atualização por classe: 150418 [Lr] Data última revisão: 150418 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 150203 [St] Status: MEDLINE [do] DOI: 10.1002/elps.201400232

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[PMID]: 25490177 [Au] Autor: Chen Z; Greaves TL; Caruso RA; Drummond CJ [Ad] Endereço: Particulate Fluids Processing Centre (PFPC), School of Chemistry, The University of Melbourne , Melbourne, Victoria 3010, Australia. [Ti] Título: Amphiphile micelle structures in the protic ionic liquid ethylammonium nitrate and water. [So] Source: J Phys Chem B;119(1):179-91, 2015 Jan 08. [Is] ISSN: 1520-5207 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Micelles formed by amphiphiles in a protic ionic liquid (PIL), ethylammonium nitrate (EAN), were investigated using synchrotron small-angle X-ray scattering and contrasted with those that formed in water. The amphiphiles studied were cationic hexadecyltrimethylammonium chloride (CTAC) and hexadecylpyridinium bromide (HDPB) and nonionic poly(oxyethylene) (10) oleyl ether (Brij 97) and Pluronic ethylene oxide-propylene oxide-ethylene oxide block copolymer (P123). The scattering patterns were analyzed using spherical, core-shell, and cylindrical scattering models. The apparent micelle shape and size of the surfactants and the block copolymer in the PIL have been reported. At low amphiphile concentrations (<10 wt %) spherical micelles were preferentially formed for all the amphiphiles in EAN. The micelles formed by the two cationic amphiphiles in EAN and water were similar, though different scattering models were required predominantly due to the ionic nature of EAN. The two nonionic amphiphiles formed micelles with similar core radii in water and in EAN. However, the micelle shells composed of ethylene oxide groups fitted to a significantly thicker layer in water compared to EAN. At high concentrations (>10 wt %) in EAN and water, there was a preference for cylindrical micelles for CTAC, HDPB, and Brij 97; however, the P123 micelles remained spherical. [Mh] Termos MeSH primário: Líquidos Iônicos/química Compostos de Amônio Quaternário/química Tensoativos/química Água/química [Mh] Termos MeSH secundário: Compostos de Bis-Trimetilamônio/química Micelas Estrutura Molecular Óleos Vegetais/química Poloxaleno/química Polietilenoglicóis/química Compostos de Piridínio/química Espalhamento a Baixo Ângulo Síncrotrons [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S. [Nm] Nome de substância: 0 (Bis-Trimethylammonium Compounds); 0 (Ionic Liquids); 0 (Micelles); 0 (Plant Oils); 0 (Pyridinium Compounds); 0 (Quaternary Ammonium Compounds); 0 (Surface-Active Agents); 0 (cethyltrimethylammonium chloride); 0 (hexadecylpyridinium bromide); 0 (pluronic block copolymer P123); 059QF0KO0R (Water); 22113-86-6 (ethylammonium); 30IQX730WE (Polyethylene Glycols); 9003-11-6 (Poloxalene); 9004-98-2 (polyethylene glycol oleyl ether) [Em] Mês de entrada: 1602 [Cu] Atualização por classe: 150108 [Lr] Data última revisão: 150108 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 141210 [St] Status: MEDLINE [do] DOI: 10.1021/jp509557z

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[PMID]: 25000531 [Au] Autor: Gospodarczyk W; Szutkowski K; Kozak M [Ad] Endereço: Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University , ul. Umultowska 85, PL61614 Poznan, Poland. [Ti] Título: Interaction of bovine serum albumin (BSA) with novel gemini surfactants studied by synchrotron radiation scattering (SR-SAXS), circular dichroism (CD), and nuclear magnetic resonance (NMR). [So] Source: J Phys Chem B;118(29):8652-61, 2014 Jul 24. [Is] ISSN: 1520-5207 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: The interaction of three dicationic (gemini) surfactants-3,3'-[1,6-(2,5-dioxahexane)]bis(1-dodecylimidazolium) chloride (oxyC2), 3,3'-[1,16-(2,15-dioxahexadecane)]bis(1-dodecylimidazolium) chloride (oxyC12), and 1,4-bis(butane)imidazole-1-yl-3-dodecylimidazolium chloride (C4)--with bovine serum albumin (BSA) has been studied by the use of small-angle X-ray scattering (SAXS), circular dichroism (CD), and (1)H nuclear magnetic resonance diffusometry. The results of CD studies show that the conformation of BSA was changed dramatically in the presence of all studied surfactants. The greater decrease (from 56 to 24%) in the α-helical structure of BSA was observed for oxyC2 surfactant. The radii of gyration estimated from SAXS data varied between 3 and 26 nm for the BSA/oxyC2 and BSA/oxyC12 systems. The hydrodynamic radius of the BSA/surfactant system estimated from NMR diffusometry varies between 5 and 11 nm for BSA/oxyC2 and 5 and 8 nm for BSA/oxyC12. [Mh] Termos MeSH primário: Compostos de Bis-Trimetilamônio/química Dicroísmo Circular Espalhamento a Baixo Ângulo Soroalbumina Bovina/química Tensoativos/química Síncrotrons Difração de Raios X [Mh] Termos MeSH secundário: Animais Bovinos Difusão Espectroscopia de Ressonância Magnética Ligação Proteica Estrutura Secundária de Proteína Rotação [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T [Nm] Nome de substância: 0 (Bis-Trimethylammonium Compounds); 0 (Surface-Active Agents); 0 (cethyltrimethylammonium chloride); 27432CM55Q (Serum Albumin, Bovine) [Em] Mês de entrada: 1509 [Cu] Atualização por classe: 171116 [Lr] Data última revisão: 171116 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 140708 [St] Status: MEDLINE [do] DOI: 10.1021/jp5047485

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[PMID]: 24717174 [Au] Autor: Carvalho JW; Carvalho FA; Batista T; Santiago PS; Tabak M [Ad] Endereço: Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil. Electronic address: jwilsonqi@hotmail.com. [Ti] Título: Cetyltrimethylammonium chloride (CTAC) effect on the thermal stability of oxy-HbGp: dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) studies. [So] Source: Colloids Surf B Biointerfaces;118:14-24, 2014 Jun 01. [Is] ISSN: 1873-4367 [Cp] País de publicação: Netherlands [La] Idioma: eng [Ab] Resumo: Glossoscolex paulistus (HbGp) hemoglobin is an oligomeric protein, displaying a quaternary structure constituted by 144 globin and 36 non-globin chains (named linkers) with a total molecular mass of 3.6MDa. CTAC effects on the oxy-HbGp thermal stability were investigated, by DLS and SAXS, at pH 5.0, 7.0 and 9.0. DLS data show that the oxy-HbGp-CTAC interactions induce a significant decrease of the protein thermal stability, with the formation of larger aggregates, at pH 5.0 and 7.0. In the acidic pH, oxy-HbGp 0.5mg/mL, undergoes a partial oligomeric dissociation, on going from 0.2 to 0.6mmol/L of CTAC, accompanied by a decrease in the Dh values from 27±1 to 22±1nm. It is observed, for the first time, that in the absence and in the presence of CTAC, oxy-HbGp undergoes a partial oligomeric dissociation, with increase of temperature, before denaturation and aggregation at pH values 7.0 and 5.0. SAXS data show that oxy-HbGp undergoes denaturation at 60°C, in the presence of CTAC, pH 5.0. At neutral pH 7.0, the aggregation process starts at 20°C, with increase of Rg and Dmax parameters. At both pH values, 5.0 and 7.0, the denaturation and aggregation are accompanied by the sedimentation of the aggregates. At pH 9.0, oxy-HbGp is totally dissociated at 40°C, in the presence of 0.2mmol/L of CTAC, while in the presence of 0.4mmol/L of surfactant the aggregation process starts at 20°C, with the full denaturation of protein at higher temperature. Finally, our data show, for the first time, that the oligomeric dissociation is an important step in the thermal denaturation of oxy-HbGp, in the presence of CTAC, independently of both the pH and the protein concentration. [Mh] Termos MeSH primário: Compostos de Bis-Trimetilamônio/farmacologia Luz Oligoquetos/química Oxiemoglobinas/química Espalhamento a Baixo Ângulo Temperatura Ambiente Difração de Raios X [Mh] Termos MeSH secundário: Animais Hidrodinâmica Concentração de Íons de Hidrogênio Modelos Moleculares Tamanho da Partícula Estabilidade Proteica/efeitos dos fármacos [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T [Nm] Nome de substância: 0 (Bis-Trimethylammonium Compounds); 0 (Oxyhemoglobins); 0 (cethyltrimethylammonium chloride) [Em] Mês de entrada: 1501 [Cu] Atualização por classe: 140520 [Lr] Data última revisão: 140520 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 140411 [St] Status: MEDLINE

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[PMID]: 24095792 [Au] Autor: Carvalho FA; Carvalho JW; Biazin E; Santiago PS; Tabak M [Ad] Endereço: Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil. [Ti] Título: Characterization of Rhinodrilus alatus hemoglobin (HbRa) and its subunits: evidence for strong interaction with cationic surfactants DTAB and CTAC. [So] Source: Comp Biochem Physiol B Biochem Mol Biol;167:23-9, 2014 Jan. [Is] ISSN: 1879-1107 [Cp] País de publicação: England [La] Idioma: eng [Ab] Resumo: Rhinodrilus alatus is an annelid and its giant extracellular hemoglobin (HbRa) has a molecular mass (MM) of 3500kDa. In the current study, the characterization of MM values of the HbRa subunits, and the effects of surfactants and alkaline pH upon HbRa stability were monitored. Electrophoresis, MALDI-TOF-MS and AUC show that the MM values of HbRa subunits are very close, but not identical to the Glossoscolex paulistus hemoglobin (HbGp). The monomer d is found to exist in, at least, two isoforms: the main one, d1, displays a MM of 16,166±16Da, and the second one, d2, is less intense with MM of 16,490±20Da. For the trimer abc and tetramer abcd, single contributions around 51,470Da and 67,690Da were observed, respectively. Finally, the monomers a, b, and c, present MM values of 17,133, 17,290 and 15,506Da, respectively. Both CTAC and DTAB interact strongly with HbRa, and up to seven surfactant molecules are bound to the protein. On the other hand, spectroscopic studies show that HbRa is more stable at alkaline pH, as compared to HbGp. Thus, our data suggest that alkaline medium, up to pH10.0, induces the oligomeric dissociation, without promoting the subunits unfolding and heme iron oxidation. Our results suggest that the MM of the annelid hemoglobin subunits is conserved to a great extent in the evolution process of these species. [Mh] Termos MeSH primário: Compostos de Bis-Trimetilamônio/metabolismo Hemoglobinas/metabolismo Oligoquetos Subunidades Proteicas/metabolismo Compostos de Amônio Quaternário/metabolismo Tensoativos/metabolismo [Mh] Termos MeSH secundário: Animais Hemoglobinas/química Concentração de Íons de Hidrogênio Oxiemoglobinas/química Oxiemoglobinas/metabolismo Ligação Proteica Estabilidade Proteica Estrutura Quaternária de Proteína Subunidades Proteicas/química [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T [Nm] Nome de substância: 0 (Bis-Trimethylammonium Compounds); 0 (Hemoglobins); 0 (Oxyhemoglobins); 0 (Protein Subunits); 0 (Quaternary Ammonium Compounds); 0 (Surface-Active Agents); 0 (cethyltrimethylammonium chloride); 15053-09-5 (decyltrimethylammonium) [Em] Mês de entrada: 1409 [Cu] Atualização por classe: 131202 [Lr] Data última revisão: 131202 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 131008 [St] Status: MEDLINE

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